Questions and postings pertaining to the usage of ImageMagick regardless of the interface. This includes the command-line utilities, as well as the C and C++ APIs. Usage questions are like "How do I use ImageMagick to create drop shadows?".
We tried your command with the latest release of ImageMagick, 6.3.1-2, and it worked fine. Not sure why its failing for you with 6.2.2. We would need a stack trace to investigate further.